Preheat the oven to 400° F. Pierce the potatoes a few times with a fork and place on a baking sheet. Bake for 35 to 45 minutes, or until tender but not mushy. Let cool for fifteen minutes, before chopping into 1/2-inch cubes. If you prefer, you can also peel and steam the sweet potatoes.
Heat the olive oil in a large skillet over medium high heat. Add the onion and sauté for 5 to 8 minutes, or until the onion is just turning golden. Add the tempeh cubes and sauté them until they're golden brown (about 7 or 8 minutes).
Add the tamari, turmeric, smoked paprika, mustard, and a quarter cup of broth. Finally add the cooked sweet potato and use a spoon to mash the potatoes and mix all of the ingredients together. Add the greens, and allow them to wilt. When the leaves turn a bright green, add the red pepper flakes, and season to taste. Serve warm.